Stem cells hold the promise to revolutionize future reparative medicine through the development of stem cell-based therapies. Transplanting stem cells (either embryonic or adult derived) into damaged myocardium is emerging as a novel means for acute repair and as an alternative to organ transplantation or ventricular assist devices in the treatment of end-stage heart failure. The crux for the success of this therapy will lie in being able to manipulate proliferating ES cells to differentiate specifically into cardiac muscle upon demand, and to predict which patients will benefit from such intervention. An alternative approach is to harness the endogenous stem cells and remaining viable myocytes to regenerate the needed myocardium. This could be accomplished if a contusive environment at the site of injury could be therapeutically produced through the use (or augmentation) of soluble proteins and or paracine factors.
Existence of adult stem cells in mature tissues and organs such as bone marrow, brain, skin or liver has been demonstrated. Although adult stem cells are mostly considered to differentiate into cell types of tissue of their origin, they have also been found to form specialized cell types of other tissues. This transdifferentiation was reported for bone marrow stem cells, which can differentiate into e.g. cardiac cells (myocytes) and can induce cardiac regeneration. Although the heart has for considerable time been considered to be a terminally differentiated organ with cells not able to self-regenerate after injury or damage, the discovery of stem cells residing in heart has opened the possibility of their use for autologous heart cell repair. First reports about adult cardiac stem cells (CSCs) appeared in 2003 and from that time, the attempts to find the procedures for their isolation and expansion into sufficient quantity for therapeutic purposes have been made. Recently, successful methods for isolation and expansion of adult cardiac stem cells from heart biopsy specimens were reported. Endomyocardial biopsy specimen grown in primary culture developed spherical multicellular clusters, cardiospheres (CSps), which can be further plated yielding in cardiosphere-derived cells (CDCs)—expansion step to obtain reasonable numbers of cells for transplantation from small specimens in a timely manner. Cardiospheres and CDCs exhibit properties of stem cells, expressed certain markers characteristic for stem cells and promoted cardiac regeneration and function in a mouse infarct model.